iSpindle - DIY Electronic Hydrometer

[jehochanan]

Hi, I sovled the problem with flashing wemos. It was a mistake in soldering. Now it works, but the problem is it sends the data to ubidots only when I turn it on or reset it. I set the interval to 10s (and tried it several times with various intervals). Someone else with this problem or some solution? Thanks a lot in advance.

 

[pocketmon]

What, I can deduct from the hobbybrauer.de forum is that you need to set the iSpindel at between 20-25 deg at 0 Plato to perform / allow the calibration test to be set up properly?

I trust others will agree that my interpretation of this from the hobbybrauer.de forum is correct?

I got the information from this document:

https://github.com/universam1/iSpindel/blob/master/docs/iSpindelPCB.md

at 19.

19. Spindel trimmen

Vorschlag für etwa 25° Neigung in Leitungswasser
Vorschlag für etwa 15° Neigung in Leitungswasser

google translated it to

19. Trim the spindle

Suggestion for approximately 25 ° inclination in tap water
Proposal for approximately 15 ° inclination in tap water

 

[Mikmonken]

OK with a little (read a lot) of help from GromitDJ I've pulled together a first bash of the board design, all the files are here hopefully that link works, the board is 30mmx40mm and should slide in nicely to the sled, and the switches should work too (unlike the shoddy soldering on the board I'm currently using.

I've ordered a few board from pcbs.io and if it all works out I'll drop a link to the shared board.

comments suggestions appreciated.

Cheers

View attachment Schematic - iSpindel.pdf

 

[rdiaz82]

OK with a little (read a lot) of help from GromitDJ I've pulled together a first bash of the board design, all the files are here hopefully that link works, the board is 30mmx40mm and should slide in nicely to the sled, and the switches should work too (unlike the shoddy soldering on the board I'm currently using.

I've ordered a few board from pcbs.io and if it all works out I'll drop a link to the shared board.

comments suggestions appreciated.

Cheers

Hi!
A very good schematic, just one question!! The Wemos power supply is attached to the 5V pin instead of the 3.3V pin?

 

[Mikmonken]

Hi!
A very good schematic, just one question!! The Wemos power supply is attached to the 5V pin instead of the 3.3V pin?

It's based on the original wiring that is on GitHub so the connections mirror that, I don't think anything is connected to the 3.3v pin on the original circuit.

I could be completely wrong though.

 

[Klooid]

Hi Mikmonken,

Thank you for sharing the schematic with us, which is very much appreciated.

Cheers.

 

[rdiaz82]

This is something that I want to check (currently I'm waiting by the slow Chinese boat xD with my components).

In theory with the battery and the charger you will get a voltage around 3.7V at the battery output so I don't know how will work the 5v voltage regulator only with 3,7V. Instead using the 3,3V pin the input voltage regulator on this pin will works fine.

Anyway this only theory I have to check it by myself

 

[rdiaz82]

I have checked the Wemos schematics and the input voltage regulator at 5v pin convert the voltage to 3,3V and the minimum input voltage for this regulator is 2,2V, so in consequence with 3,7V it will work fine

 

[day_trippr]

Using 80mA (total SWAG) as the worst-case load for the D1 Mini and the rest of the components, the RT9013-33 LDO spec shows the 3.3V output will start to track the input voltage once the battery drops to 3.35 volts.

That means once the battery voltage drops to 3.35, every further drop will be reflected linearly at the regulator output, until the battery drops below 2.2V where the RT9013-33 totally loses its mind.

Of course the Mini may have already taken a dirt nap around 2.97 VBAT.
So there's not a lot of head room in this scheme...

Cheers!

 

[rdiaz82]

Using 80mA (total SWAG) as the worst-case load for the D1 Mini and the rest of the components, the RT9013-33 LDO spec shows the 3.3V output will start to track the input voltage once the battery drops to 3.35 volts.

That means once the battery voltage drops to 3.35, every further drop will be reflected linearly at the regulator output, until the battery drops below 2.2V where the RT9013-33 totally loses its mind.

Of course the Mini may have already taken a dirt nap around 2.97 VBAT.
So there's not a lot of head room in this scheme...

Cheers!

A very good explanation!!

Cheers!

 

[Mikmonken]

But as a side note to that using the specified battery and setting log intervals for 30 mins, battery life is noted to be around 3 months.

 

[Mikmonken]

I doubt it will work since even Microsoft's on-line version doesn't. The excel might have something in C# or VB because the on-line version Excel complained something about ActiveX or VB. Never mind, I've found my solution. Even iSpindel does it in other way, I am going to stick this way unless it doesn't work.



Spline was my first homework in Algorithm class and the first algorithm that came to my mind. I tried studying it on the internet, ( I was too lazy to find my text book.), but one thing kept bothering me: ERROR. The data we have has error in it and is nothing near precise. It didn't seem right to me to derive the coefficients by fitting data with errors. Therefore, I concluded that regression is the solution. I am lucky to find a Javascript library for regression, and the example code even has a chart.

https://github.com/Tom-Alexander/regression-js

This library also supports exponential and other regression. If my real data doesn't seem to be polynomial, I can adapt quickly.

@pocketmon did you ever manage to sort the issue with OS X and excel? I'm getting the error 400 code with Visual Basic and know it's an issue with Excel for Mac, so if you've worked out a way to calibrate that'd be great.

Thanks

 

[pocketmon]

@pocketmon did you ever manage to sort the issue with OS X and excel? I'm getting the error 400 code with Visual Basic and know it's an issue with Excel for Mac, so if you've worked out a way to calibrate that'd be great.



Thanks

nope. I just created a Javascript for it. I am not sure what algorithm the excel uses, but I can get the same coefficients by inputting the same dataset in the chart of the document.

 

[pocketmon]

Finally get the calibration done.

My iSpindel tilts around 37 degree in tap water with 20g at the bottom.
It will tilt like 5 degree with 25g at the bottom, so I have to stick the additional 5g at the center.

The result curve is more like a third order(x^3) instead of second order.

 

[kob22]

Did anyone try to make iSpindel with bluetooth (BLE) instead of wifi?
There is no access to wifi everywhere. Bluetooth needs less power. You could do something like beacon. Reading can be done by the application on the phone.

Does anyone have an idea what parts can be used for this?

 

[pocketmon]

Did anyone try to make iSpindel with bluetooth (BLE) instead of wifi?
There is no access to wifi everywhere. Bluetooth needs less power. You could do something like beacon. Reading can be done by the application on the phone.

Does anyone have an idea what parts can be used for this?

Yes. Please google Brewometer or TILT hydrometer.

 

[kob22]

I know this project, but it is commercial. I'm looking for a DIY idea.

 

[pocketmon]

I know this project, but it is commercial. I'm looking for a DIY idea.

Yes. You can find the source in this discussion:

https://www.homebrewtalk.com/showthread.php?t=385352&page=11

You should already find that it is based on Blue Bean.

That should be enough for you to make one.

 

[BrunDog]

I know this project, but it is commercial. I'm looking for a DIY idea.

I am just curious and have to ask... why? For $120 you get something that works and is supported. You would dump hours upon hours doing a one-off. Your time should be worth much more than that.

Now, if you wanted to do it just for the sake of learning, I could appreciate that. But if only for the end goal of having a hydrometer, you would save $120 but spend $1200 (or much more).

 

[kob22]

Because I can do exactly what I need (for me or for my friends). I know how to do it (except electronic, this is my weak point) and I like it (hobby? )

 

[BrunDog]

Still curious.... what do you need? A hydrometer reports SG. What else do you want it to do?

 

[NeoBrew]

Still curious.... what do you need? A hydrometer reports SG. What else do you want it to do?

I respect the answer from an economic standpoint. You are right about the money.

But asking this question on a homebrew forum is kind of odd. DIY is an ethos and a personal satisfaction thing.

For example, there is NO good economic reason to make your own beer. If you factor in equipment, ingredients, energy, AND your time there is little chance you are not paying more for your homebrew than you would to buy commercial beer.

 

[BrunDog]

Touché! Fair enough and great point.

I think the beer I make is much better than that I can buy, so that's how I justify it. But I suppose the same argument can be made of the DIY hydrometer.

Like everything else in life, it' the value you place on things which drives decisions

 

[ElChangoGuero]

Finally get the calibration done.

My iSpindel tilts around 37 degree in tap water with 20g at the bottom.
It will tilt like 5 degree with 25g at the bottom, so I have to stick the additional 5g at the center.

The result curve is more like a third order(x^3) instead of second order.

im about to do the calibration as well, any tips? also did you do the easy or the improved method?

 

[pocketmon]

easy one. I used almost one pound of sugar. I needed to use two containers, one gallon pitcher and a salad bowl. The pitcher is not wide enough when the tube floats vertically, while the bowl is not deep enough when the tube floats horizontally.
It is hard to dissolve so much sugar in cold water. 18 plato is the best I can do. You might need to hear the water to dissolve more sugar, but you need to wait until it's cool.

 

[Mikmonken]

I did the improved method and used a 1 gallon water bottle with the lid cut off. Wide enough for the spindle to lay flat and deep enough for me to drop a hydrometer in to read the gravity. I'm using bread yeast to ferment.

Downside it's taking ages once it's finished I'll post and image of my curve I think the carbonation does keep it more horizontal for the first few days

 

[ElChangoGuero]

anybody experiencing issues with the read intervals? mine works fine for a while but it looks like it randomly checks the reading

 

[pocketmon]

anybody experiencing issues with the read intervals? mine works fine for a while but it looks like it randomly checks the reading

What is your report interval?
Mine is set to 10 minutes, and it works fine.

 

[ElChangoGuero]

What is your report interval?
Mine is set to 10 minutes, and it works fine.

lol i had it in 10 s but i changed it now to 5min and looks like its working like a charm! will keep testing though

 

[BrunDog]

What is your report interval?

Mine is set to 10 minutes, and it works fine.

Impressive that the reading doesn't vary at all.